


What You Don't Know

by gingerbread_lesbian



Category: Harry Potter - J. K. Rowling
Genre: Alternate Universe - Canon Divergence, F/F, Lesbian Sex, Multi, Time Travel
Language: English
Status: Completed
Published: 2015-02-04
Updated: 2015-02-04
Packaged: 2018-03-10 13:05:35
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,368
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3291362
Author URL: https://archiveofourown.org/users/gingerbread_lesbian/pseuds/gingerbread_lesbian
Summary: <blockquote class="userstuff">
              <p>Sian is a student from another school who has been magically brought to Hogwarts where Lily Evans, perfect little prefect, has been showing her around. Lily has a secret, though, a secret romance with another female student, the poisonous Bellatrix Black. What happens when the jealous Bellatrix decides that enough is enough? She doesn't like this new girl following Lily around everywhere! || Almost entirely just smut XD A gift for a friend <3 Very little plot, but humorous and smutty which is nice lol. Enjoy~!</p>
            </blockquote>





	What You Don't Know

**Author's Note:**

> What You Don’t Know.  
> 2015  
> Dedication: Aimee ;D <3  
> For anyone else: This is almost completely smut in an AU little fantasy world. There is simply no plot at all XD You have been warned.

“How do you girls think that you could possibly explain this atrocious behavior?” Professor McGonagall’s words were piercing and pointed further with horror and disappointment. Tears ran down the face of Lily Evans as she trembled between her co-conspirators, Bellatrix Black, the most dangerous of all Slytherin purebloods, and Sian Strauth, the victim of a spell misfire that sent her back in time 30 or so years.

How indeed /had/ they gotten to this point, you may ask? Well, let’s return to the beginning of this ordeal and I will fill you in with /all/ of the details:

* * *

Sian Strauth had appeared mysteriously three nights prior and had met Bellatrix Black and Lily Evans at the most inopportune moment possible. She had popped into existence in the bell tower of Hogwarts and, within her first minutes at Hogwarts, tripped, falling sprawled out over the cold stones that covered the floor. She quickly realized that she had tripped over two people when she heard two female voices grunting and groaning in pain. Her apologies did not last long before she was stunned speechless at seeing what she had tripped over… the two girls were naked, panting! Bellatrix had nearly strangled the girl, but Lily managed to stop her and calm her down.

Sian, stunned by the awkwardness of the situation, was quickly informed that Lily and Bellatrix were lovers, but because of their different blood statuses and houses as well as their shared status as members of the fairer sex, their relationship had to remain, above all, a secret. Sian, it turned out, was from the future where, as she explained, apparently lesbians were free to be together… at least a little more than the stifling there was in the 1970s magical world. Important part, however, is later, what happened after. You don’t really care about how they got together, did you? You want to see them undressing and attacking one another like rabbits.

So Lily took Sian to the Headmaster and got permission to care for her during her indefinite stay at Hogwarts school. Bellatrix did not like this one bit because it meant less time alone with Lily which was already dwindling because of Bellatrix’s unwitting “beard” Rodolphus and his incessant need to “stake his claim” of her body. So, one day, Bellatrix caught Lily and Sian in the hallway as they headed on their way to dinner and dragged them into the abandoned library. She pulled them further, into the back most row in the farthest corner possible before glaring at them both.

“Lily is /my/ girlfriend you dumb time-travelling bimbo.” The insult made Lily smile and Sian laugh.

“Bella, that’s rude. Sian and I are just friends, there’s no way that she…”

“Well actually, no, Bellatrix is right. I would love to plow you senseless.” Sian interrupted, smirking devilishly as she watched Bella’s face contort. Lily’s eyes widened and her cheeks turned pink.

“What??” But instead of explaining again, Sian simply grabbed the girl’s face and pulled the redhead’s lips to her own, claiming them in a passionate kiss which enraged Bellatrix. Bella opened her own mouth to shout some choice words at Sian for her foolishness, but as she did, Sian tugged her into a kiss instead, mere inches from Lily’s face, making the redhead watch.

“Sweet Merlin…” Lily muttered softly as she watched the pair tongue one another, both fighting for dominance and neither winning. A lopsided grin spread over her face as she watched, not knowing exactly whom she was rooting for to win. She didn’t even know what they were fighting for anyway. “I’d eat both of you out. You don’t have to fight over me.” The redhead purred, her voice husky with arousal. Both of the other girls instantly turned their heads, forgetting one another. Bellatrix quickly began to kiss and suck on Lily’s neck, hands running down over the ginger’s body. All three were lean and sexy bodies with Bella being tallest and Sian shortest.

Sian smirked a little bit and undid the clasp of her skirt, quickly slipping out of it. She had not been wearing panties at all so her shoes, socks, and skirt soon lay in a pile and her lower half was exposed. Bellatrix was still nipping at Lily’s neck, her fingers working on removing the buttons on Lily’s shirt, and in that instant, it was decided that the three of them were going to have sex, right there in the library.

“We have to be quiet.” Lily whispered into Bella’s hair, smirking a little bit as Bella gently bit down on her neck. Her own clothes were being removed and she suddenly yearned to see Bellatrix’s body as well. As her fingers worked, the forgotten Sian returned from watching the pair stripping one another and pushed Lily against a wall and down onto her knees. As Lily looked up, stunned a little bit, the younger girl pushed her head between her own thighs, the smile on her face telling Lily all she needed to know. She buried her face between the girl’s legs, gently sucking the little bud between Sian’s pussy lips into her mouth. Sian’s fingers threaded into the other student’s long red hair, pulling her in closer as her other arm braced her against the wall.

“Stealing my girlfriend…” Bellatrix growled softly, but not in an actually angry way. She held onto Lily’s head gently as she turned them so that Bella’s back was to the wall, Sian was pressed back into her chest and Lily was in the center of the isle. Bella couldn’t seem to quite get into it, being turned on primarily by the gasps and moans and soft sounds Lily would make when Bellatrix punished her. She was a sadist primarily. It was not the /only/ was she got turned on, but it was usually how it happened.

“Ohhhh shit… good girl…” Sian purred, smirking as she stroked the crimson locks between her legs. Lily moaned softly at the petting of her hair and the soft vibration of sound waves passed into Sian’s clit as well, making it vibrate and tingle gently. The foreign student moaned softly, her head tilting back onto Bella’s shoulder as a wave of blissful sexual pleasure rushed through her body. Bellatrix gasped softly at the gentle grind of Sian’s hips back into her own, the groan of pleasure that escaped the girl’s lips, and wrapped her arms firmly around Sian’s body, letting herself, finally get caught up in the arousal of it all, dipping her head to nip lightly at Sian’s shoulder. As a reward for playing along, Sian sped up the pace of the circles she was drawing on Bella’s clit with her fingers. The rubbing was like nothing else. Even though Bellatrix masturbated, fairly frequently, and used the same motions as Sian was, having another hand pleasuring her was even better somehow. It paled in comparison to Lily’s tongue on her clit, but Lily’s mouth was busy working at Sian’s cunt. That made jealousy well up a little in Bellatrix’s belly, but she held it in as best she could, letting it out on Sian’s shoulder every so often with a little bite.

It was not long before Sian was getting ready to have an orgasm. A mix of being tipsy and having gone so long without a good, proper orgasm, Sian was eager. Plus, Lily’s tongue felt amazing. The redhead was a pro at suckling on the soft, wet flesh of ladies’ parts from being Bellatrix’s little whore. Whenever Bella wanted to get off, she could go to Lily and demand it. It was never unwelcome. Lily loved pleasing Bellatrix almost more than she liked being pleasured herself. To watch Bella wriggle in pleasure as she tried not to cum so early was the greatest turn on Lily had ever found.

“Fuck, Lily… that mouth of yours…” Sian whispered, clenching her teeth as she tried to hold on.

“That mouth is mine.” Bellatrix growled softly and Sian laughed a little before leaning back into Bellatrix, her orgasm crashing down on her in an instant. Bella’s strong arms kept her standing as Lily sucked and mouthed her clit through the entire period of trembles, muffled cries and sounds of pleasure that bordered on pain they were so intense. Once the younger girl had finished, Bellatrix gently let go of her and Sian’s knees were so weak that she tumbled forward, almost kneeing Lily who caught her and lay her on the ground.

She was tired, satisfied, and spent, but Sian didn’t like being on the bottom and she quickly flipped her and Lily’s positions on the floor. After a moment, she straddled the redhead’s face.

“Lick it clean.” She ordered and Lily smirked, instantly setting to work lapping up the sweet juices from between the girl’s legs and pussy. That was, until she felt hands sliding up from her ankles up past her knees.

“My girlfriend, my turn.” Bellatrix suddenly insisted, grabbing the outsides of Lily’s thighs and pulling her across the carpet until their hips collided. The rubbing of their bodies made Lily gasp out a throaty moan as she looked up at the wild-haired Slytherin between her legs. Bella’s eyes were predatory as if she were ready to swallow Lily whole, and for a moment, as she leaned down quickly, Bellatrix seemed actually about to do just that. Instead, their lips met in a bruising and desperate kiss as the older girl grasped Lily’s wrists and pinned them to the bristly carpet that covered the library floor.

“This is not fair at all.” Sian huffed, smirking a little when Bellatrix’s lips left Lily’s to snap some response. The younger girl captured Bellatrix’s lips with her own and Lily’s emerald eyes watched and grew round. Her heart began to pound all over again, her breath quickening as she watched the girls kissing just over her head. Bellatrix’s hips began to gently grind into Lily’s, bringing the redhead back to attention. She smirked and wriggled to intertwine their legs, giving Bellatrix a thigh to hump. With the extra pressure of Lily’s leg, Bellatrix groaned softly into Sian’s lips, pulling the girl closer by the collar of her shirt.

“Hush, darling.” Lily whispered and smirked as she leaned up. She propped her shoulders against Sian’s belly to keep herself upright as she pulled one of Bella’s nipples into her mouth. Sian’s hand dropped to stroke her hair gently and Bellatrix’s wrapped around her to keep her up and pressed to the other girl’s tit. Laughing softly into Bella’s chest, Lily ran her hot tongue over the sensitive nipple, making Bellatrix groan once more and press harder on the back of Lily’s head, begging silently for more. Being ever the submissive and gracious partner, Lily complied with the silent command, drawing the little bud between her lips and suckling softly. Suddenly, a soft yelp of pain made Lily pull away in alarm, but Bella’s hand kept her from going far. From her place, Lily could see the reddening of a bite mark on Bella’s lower lip which made Lily’s eyes grow huge. Sian was smirking though and the wetness growing on the skin of Lily’s leg told her that Bellatrix liked that more than she’d ever admit. Lily smirked, then, as well and returned her attention to her lover’s chest, moving to the other breast as Bellatrix’s grinding against her thigh grew more rapid and needy.

“Lily’s good at sucking. Isn’t she, Bella?” Sian cooed gently as she leaned down to kiss Lily’s cheek as a little “good girl” show of affection. Bella nodded a little, trying to keep herself from moaning out at the myriad of sensations. Lily’s skin against her clit as she rubbed it against the redhead, the girl’s mouth around her nipple, Sian’s fingers running along her sides, all had Bellatrix was ready to burst at the seams. Lily could feel it in the way that Bella’s fingers massaged and clung to her hair. She was close. Meanwhile, Sian was turning her attention to Lily who was so busy caring for the other two that she had gone almost wholly neglected.

Her tongue ran along Lily’s neck before she found a spot she liked, just above the juncture of the throat and shoulder blade. She nipped, hard, making Lily moan into Bella’s tit which brought Bellatrix’s orgasm on in a single, earth-shattering second. Sian’s lips had to leave their spot to crush into Bella’s and keep her silent as the Slytherin hit her climax hard. Lily’s hands found Bella’s hips which began to slam hard and fast into the redhead’s body. It nearly hurt, but the desperation in Bellatrix’s thrusts only served to soak Lily’s own arousal to an indescribable point. Eventually, Bella’s thrusts stopped completely, a hand moving between her legs to maintain pressure and a little movement, but she fell a little into Lily’s shoulder, knocking the redhead back into Sian’s lap. Lily wrapped an arm around the now trembling and whimpering Bellatrix, the other hand stroking at the crazy curls on her girlfriend’s head.

“Easy, love…easy…” She purred into the brunette’s curls and kissed the top of her head. Sian gently rolled Bellatrix off of Lily and smirked, wiping sweat from the spent Slytherin’s brow. The respite only lasted a moment before Sian’s gazes turned back to Lily. She returned to the position they were in before, with Lily’s back against Sian’s chest. The black-haired girl wrapped an arm around Lily’s waist, her skin almost burning hot to the touch as it slid across Lily’s belly. This time, though, Lily was positioned facing Bellatrix who lay panting on the floor, her hand at her crotch to ease the pulsating of the sensitive flesh. Sian was behind, watching Bellatrix over the back of Lily’s shoulder as her tongue and teeth grazed over the soft surface of Lily’s skin, moving over the girl’s neck like a vampire thirsting to bite into it, but never sinking in, just running just along her goosebumps. The sensation made Lily shiver and for more gooseflesh to appear across her chest and arms, a shuddering sigh leaving her lips.

“Like it gentle, eh? I bet you’re not used to it with this one all over you.” Sian cooed as she nipped at Lily’s earlobe, suckling on it gently as her free hand cupped one of the redhead’s perky, young tits. Her other hand was moving down from the Gryffindor’s belly button, running over short ginger hairs that covered her delicate womanhood. Lily gasped and her hand went to the arm wrapped around her chest, massaging the far breast. Her fingernails would have left impressions in the girl’s forearm if they hadn’t been clipped so short. The attempt made Sian chuckle darkly in her ear, her hand pressing on until it found the wetness untouched since the beginning of all of this. “Naughty, naughty girl… You’re this wet just from watching Bella and I cum? We haven’t even touched you.” Sian criticized softly, smirking mischievously.

Brown eyes flickered from Lily’s cheek to Bellatrix across the narrow isle. The Slytherin was sitting up to watch, enjoying the look on Lily’s face clearly because the hand between the Black girl’s thighs was moving slowly, rubbing circles in the hot, wet flesh. Lily must have been looking as well because Sian could feel more wetness seeping onto her fingers. She smirked.

“Like that, eh?” Sian teased and Lily colored, but she grew wetter at being caught in the act. Sian smirked and slid her nearly-dripping fingers up into Lily’s awaiting cunt. The sound Lily made turned both of the other girl’s on at once. It was a strangled sound as if Lily were trying her very hardest to hold it back, but it simply felt too perfect and she could not keep it in a moment longer. The younger girl grinned at her success and the three fingers she’d buried in Lily’s pussy began to move. Sometimes she would simulate a man’s parts, thrusting in and pulling out in a rhythm, but when her arm would get tired, she would curl her fingers which always proved to make the redhead wriggle lightly.

“Bella…” Lily whimpered softly to the girl masturbating in front of them. The sadists head tilted at the call of her name and she gazed at Lily questioning what she wanted. After a moment, she smirked and kneeled, figuring out what Lily wanted. She kissed her deeply and, the second their lips met, Lily moaned out into her girlfriend’s lips with a satisfied sound to it. Lily was the only one worried about getting caught… but that was probably because, of the three of them, she knew the most about Madam Pince’s schedule and probably knew subconsciously that, in all the time they were back here fucking, the woman would have returned from her dinner and would have settled down at the counter with a book and cup of tea, a silent activity which would not have disguised the sounds of the three girls making love at the back of the library.

Lily was the only one worried because she was the only one smart enough to know the probability of them getting caught… in fact, she was right in her calculation that it was growing incredibly high because not two minutes after she was able to moan into Bellatrix’s mouth, but quite a while before she would have been able to reach her own orgasm, the sound of the librarian’s shocked and horrified gasp shattered their love fest. It was most certainly a sight to be seen! The smell of feminine juices hanging in the air, Lily Evans pressed between Sian Strauth and Bellatrix Black, getting fingered senseless by the former and kissed passionately by the latter… all in a certain degree of undress. Sian was the only one with her shirt on, though it was hanging off of her shoulders and her bra was missing, if she’d ever been wearing one at all. Lily’s socks were still on and Bellatrix was still wearing panties, though now they were quite see-through with the soaked state of them. All three were red-faced, breathless, and covered in a thin sheen of sweat from their half hour of exertion.

“Go to the lavatory. This INSTANT. Clean yourselves up. I am calling Professors McGonagall and Slughorn to deal with you. Dumbledore as well.” The librarian scolded, fumbling as little to get out of the girls’ ways as the three stood from the floor. There were articles of clothing all over the floor along with various wet spots, the origins of which Madam Pince DID NOT want to know.

* * *

And this was how they got here. We’re all caught up and you see why Lily is so restless. Poor girl was not only embarrassed and mortified that her beloved Professor McGonagall had to hear of this, but she was also aching for release. No amount of humiliation would be able to undo the work that Sian had accomplished in bringing Lily to this state.

“You girls must sit here… all night if you must… and contemplate what you have done. We are severely disappointed in your behavior.” Professor McGonagall said in her cool, haughty voice as she shook her head in dismay.

“O…ohhh yes… um… in…indeed… very disappointed…” The red-faced Slughorn added as he bumbled and trembled. He was more discomforted than the three offenders… Of them, Lily was the worst. Bellatrix was the most desperate that word not be sent to their families, and Sian seemed cool as a cucumber as she sat there. Lily presumed that she was used to this, being in trouble with professors… as well as the fact that she did not go to this school and was from the future and had literally nothing to worry about or lose in this situation. Lily gazed at Bellatrix who looked ready to murder every owl in the school to keep word from reaching Black Manor.

* * *

“It’ll be alright, darling.” Lily whispered as the professors left the girls to contemplate their behavior. This was a horrible idea on their part because, as soon as the heavy oaken door of the detention room, an old classroom in the dungeons of the castle, Lily felt a hand on her thigh.

“Strauth, what on EARTH are you doing?!” Bellatrix hissed in an instant, her face red and not from embarrassment. Lily’s heart skipped a beat and she was at a loss for words as she saw Sian smirk from between her legs.

“Lily never got to cum. She’s probably ready to burst.” Sian said lightly and hiked up the redhead’s skirt lightly before pulling her closer by the knees. Lily was slouched in her chair, then, but did not do anything to stop the other girl. She was desperate, after all. Pink faced, Lily looked over at Bellatrix who was furious, but too terrified that the professors would return to act on her anger. She walked over to the door and sat in front of it, watching Lily’s face as it contorted at the first touch of Sian’s tongue against her pulsating clit.

“Fuck…” Lily whispered and Bellatrix could not help, but to smirk lightly. The Gryffindor’s fingers slid into the short black hair of the girl on her knees under the table and urged Sian on while the skillful digits of the younger girl slid their way back into Lily’s soaked pussy.

“Naughty girl. I hope Bellatrix punishes you later.” Sian said, the words alone making Lily tremble with delight, but also the sensation of hot breath against her clit made her moan softly. Her eyes closed, Lily did not see Bellatrix leave from the door, and her heart pounding in her ears, Lily did not hear the clicking of the lock as Bella left it either. So it was sudden when Lily was lifted up forcefully from the chair and bent over the table roughly. She gasped a little, turning her head to look up at Bellatrix who glanced at Sian and showed her where to move. Sian’s mouth and fingers took up their rhythm once more as Bellatrix bent over Lily’s back to whisper in her ear.

“No, I’m going to punish you now. You got us caught, mudblood. It’s your fault I’m going to get disowned. Because you’re a filthy little whore who can’t keep her skirt on, aren’t you?” Bellatrix hissed in her ear. Sian smirked as Lily grew even wetter and the redhead moaned into the wood of the table, nodded a little to agree with Bellatrix. “Use your words, you dumb slut.” Bellatrix warned.

“Y…yes, Be…Bellatrix…” a sharp slap against her ass cheek interrupted Lily’s reply.

“Mistress.”

“Yes, Mistress Bella. I’m a filthy little whore.” Lily replied and shuddered with pleasure. Bellatrix seemed satisfied, but began the punishment for being said whore. Lily ended up with possibly 10 spanks for her naughty behavior. It was hard to tell because after the fifth, she was so aroused and ready to cum that she lost count.

“Do you want to cum, whore?”

“Mmmmm yes…. Mistress, please let me…” Lily begged softly.

“I don’t think you want it badly enough.” Bellatrix said and placed her hand over Sian’s to keep it from moving inside of Lily. The sudden lack of movement made Lily wriggle further and cry out softly in dismay. Bellatrix smirked.

“PLEASE…” A slap.

“Softer.”

“Please, Mistress Bellatrix… I want to cum so badly. I’m your little whore, please do with me as you will, but please, if I don’t cum I might go batty or possibly even die.”

“Why wouldn’t I want that?” Bellatrix whispered, smirking into Lily’s ear.

“I…I wouldn’t be able to suck your clit all day if I wasn’t alive.” Lily tried to reason. Bellatrix laughed sadistically in her ear and pulled Sian’s fingers from Lily’s vagina. This made actual tears run down the redhead’s face as it became clear that Bellatrix would not allow her to climax.

A heartbeat later, though, fresh, warm fingers slid into her and Sian’s mouth began to move again. Feeling the thrust of hips into her arse, Lily moaned and smiled, realizing that Bellatrix was the one who would fuck her over the cliff of sanity. As it drew closer and closer, the orgasm curled Lily’s back and toes, her behind stuck up lightly and pushed her into an even better position to receive Bellatrix’s fingers. As they rolled over Lily’s g-spot one last time, Lily bit down, hard, into her forearm to keep from screaming with pleasure. Her fingers clawed lightly at the table beneath her as she tumbled euphorically over the top of the mountain of pleasure and came crashing down suddenly, shaking softly against the wood. Bellatrix smirked against the back of her lover’s neck and nipped softly.

“Good girl…” She whispered softly as she stroked Lily’s hair and held her gently until the last of the aftershocks died away and Lily was left sated, panting, and shivering. Bellatrix fixed her lover’s skirt and sat her back in her chair just as the professors’ shoes could be heard on the stone outside. Lily bowed her head a little, covering her face so it just looked like she was crying as Bella unlocked the door and Sian wiped her mouth gently, both returning to their chairs just as the doors swung open.

 “Oh Lily…” Professor Slughorn lamented softly. “Minerva, this has gone on long enough… These girls… what they did was surely unacceptable, but you cannot say they are the only sexually active students in the school. I suggest that we give our students each 5 detentions, deduct 30 points from Gryffindor and Slytherin and call it a day. No need to take away Lily’s prefect badge or inform Mr. and Mrs. Black of this… whole… mess.” The potions professor reasoned. Somehow that worked. Lily thanked him profusely later… her most unexpected savior. He would never know that she was not sobbing about the circumstances, but recovering from the most amazing orgasm of her life… but what you don’t know can’t ever hurt you, right?


End file.
